Risk Map Early Demonstration

ProjectLackawanna County, PA

CCO MeetingSeptember 13, 2011

Outline

Overview of Risk MAPEarly Demonstration Project ScopeSummary and ResultsQuestions

Risk MAP VisonThrough collaboration with State, Local, and Tribal entities, Risk MAP will deliver quality data that increases public awareness and leads to action that reduces risk to life and property.

Early Demo Project Scope

Develop Risk MAP ProductsChanges Since Last FIRMMulti Frequency Raster Flood Datasets

3D Flood Elevation Flood Depth

Risk Communication Datasets % Annual Chance Layer Probability of Flooding in 30 years Layer

Areas for Potential Mitigation

Early Demo Project Scope

Develop Risk MAP ProductsRisk Assessment Analysis

Using FEMA’s HAZUS SoftwareFlood Risk DatabaseFlood Risk ReportFlood Risk Map

Changes Since Last FIRM-CSLF-

What is it? GIS layer depicting the

changes in SFHA and Floodway since previous mapped FIRM

Quantifies Land Area Zone Changes Contributing Engineering

Factors (Why?) Uses:

Communication and Outreach Public Notification through

Mailings Internet Outreach Applications

Changes Since Last FIRM-CSLF-

Early Demo Results SFHA Changes

Total Area: 18 sq. miles Increase: 6.35 sq. miles Decrease: -9.85 sq. miles Net Change: -3.52 sq. miles

Floodway Changes Total Area: 2.57 sq. miles Increase: 2.35 sq. miles Decrease: 0.0 sq. miles Net Change: 2.35 sq. miles

Water Surface GridsMultiple Return Periods

What is it? GIS datasets showing 3D flood

elevations every 20 feet throughout the floodplain.

Developed using results from computer modeling and is basis for flood depth grids.

Developed for multiple flooding events (10%, 2%, 1%, 0.2%) countywide, where applicable.

AE and A Zones Uses:

Hazard Communication and Outreach

Efficient BFE Determination Could be paired with building

specific data (FFE, values, etc.) for loss estimations

Depth GridsMultiple Return Periods

What is it? GIS datasets showing flood

depths every 20 feet throughout the floodplain.

Developed by subtracting 3D flood layer from ground surface.

Developed for multiple flooding events (10%, 2%, 1%, 0.2%) countywide, where applicable.

AE and A Zones Uses:

Hazard Communication and Outreach

Loss Estimation Using FEMA’s HAZUS software.

Velocity GridsMultiple Return Periods

What is it? GIS datasets showing average

flow velocities throughout the floodplain.

Developed for new detail study only.

Developed for multiple flooding events (10%, 2%, 1%, 0.2%) countywide, where applicable.

Uses: Hazard Communication and

Outreach Risk Assessment. Combined with Depth

Information for damage potential.

Percent Annual Chance Grid

What is it? GIS layer showing the

“threshold” flood that inundates a given land area (ex. 75-year flood)

Also known as the “Percent Annual Chance Grid”

Uses: Hazard Probability

Communication Efficient / real-time flood

mapping of non-standard flood events.

Used as basis of developing the percent 30-year grid.

Percent Chance of Flooding in 30 Years Grid

What Is it? Estimates the probability of

flooding at least once during a 30 year period

Developed using the percent annual chance grids

Uses: Probability Communication Goes beyond the

traditional “in or out”phylosophy

HAZUS Loss Estimations

• Flood Losses (per census block) Computed using Census Data and multi-return depth grids

• Separate scenarios created for each return period

Areas of Mitigation Interest-AOMI-

• Dataset which identify areas where mitigation efforts could be potentially effective

• Locations were determined from the effective FIS as well as the local Hazard Mitigation Plan

Flood Risk Database

Flood Risk Report

Flood Risk Map

Questions

Thank You